1. Field of the Invention
This invention relates to well tools. More particularly, it relates to apparatus for and methods of injecting coupled pipe into a well and removing it therefrom with an improved injector apparatus which is capable of handling both coupled pipe and coil tubing with the additional capability of rotating either of these flow conductors in a well to perform downhole operations.
2. Description of the Prior Art
It is common practice to run coil tubing into and out of wells through use of a coil tubing injector. Recently, coil tubing injectors have been improved to enable them to rotate a length of coil tubing in a well to perform downhole operations. Such improved injector made it possible to add jointed, even coupled pipe, to the upper end of coil tubing in the well and to even raise or lower the pipe/coil tubing string while being rotated. Such improved injector together with methods of treating wells employing its use is the subject of U.S. Pat. No. 4,515,220 which issued on May 7, 1985 to Phillip S. Sizer, Don C. Cox, and Malcolm N. Council for APPARATUS AND METHOD FOR ROTATING COIL TUBING IN A WELL. This patent is hereby incorporated herein for all purposes by reference thereto.
Known published prior art which may be pertinent to this present appliction includes the following U.S. Pat. Nos.
______________________________________ 3,191,450 3,215,203 3,285,485 3,313,346 3,559,905 3,677,345 3,754,474 4,085,796 4,251,176 4,515,220 ______________________________________
U.S. Pat. No. 3,191,450 which issued June 29, 1965 to J. H. Wilson teaches means for rotating pipe while raising or lowering the same.
U.S. Pat. No. 3,215,203 issued to P. S. Sizer on Nov. 2, 1965. This patent teaches forcing jointed pipe into or out of a well through use of hydraulically powered snubbing apparatus.
U.S. Pat. No. 3,285,485 which issued Nov. 15, 1966 to D. T. Slator teaches injector apparatus for injecting coupled pipe into a well. Its pair of endless chains squeeze the pipe therebetween. Forces are applied to the chains through single-tree type linkages which offer a degree of flexibility which will permit a pipe coupling or other enlargement to pass through the device. This apparatus has not proved practical because the higher squeeze loads necessitated by high well pressures and/or great working depths cause the device to squeeze the pipe couplings so severely out of shape that the pipe string cannot be disassembled by unscrewing the threaded joints as the pipe string is removed from the well.
U.S. Pat. No. 3,313,346 which issued to R. V. Cross on Apr. 11, 1967 teaches methods of and apparatus for working in a well without a derrick through use of coil tubing and a coil tubing injection apparatus.
U.S. Pat. No. 3,559,905 issued to Alexander Palynchuk on Feb. 2, 1971. This patent teaches apparatus and methods for running sucker rods into a well and removing them therefrom continuously through use of an injection device operating in the manner of a coil tubing injector.
U.S. Pat. No. 3,677,345 which issued on July 18, 1972 to P. S. Sizer discloses apparatus and method for making up a pipe string as the string is run continuously into the well, or disassembling the string as it is removed continuously from the well.
U.S. Pat. No. 3,754,474 issued to Alexander Palynchuk on Apr. 28, 1973 and discloses gripper pads for use in drive chains in sucker rod injectors.
U.S. Pat. No. 4,085,796 was issued to Malcolm N. Council on Aug. 25, 1978 and discloses hydraulically powered apparatus for snubbing pipe into or out of a well, this apparatus having a plurality of hydraulic cylinders which can be used in various combinations to provide a range of speeds and forces.
U.S. Pat. No. 4,251,176 which issued to Phillip S. Sizer, et al. on Feb. 17, 1981 discloses a hydraulically actuated pipe snubbing apparatus wherein the length of the stroke of the pipe moving portions is equal to twice the length of the hydraulic cylinder.
U.S. Pat. No. 4,515,220 issued to Phillips S. Sizer, Don C. Cox, and Malcolm N. Council on May 7, 1985. This patent discloses a coil tubing injector and a quill therefor. This apparatus permits running coil tubing into a well to desired depth, cutting the coil tubing, placing a quill around the upper end portion of the coil tubing, adding jointed pipe to the upper end of the coil tubing, gripping the pipe with a rotating gripper on the quill, and gripping the quill in the coil tubing injector. The coil tubing can be lowered further by adding more pipe to its upper end, can be rotated by the rotatable gripper on the quill, and can, if desired, be moved longitudinally and rotatably simultaneously as required, all for performing operations downhole, such as light drilling operations for removing sand bridges and similar obstructions.
Of the prior patents discussed above, U.S. Pat. Nos. 3,285,485 to D. T. Slator, 3,559,905 to Alexander Palynchuk, and 4,515,220 to Phillip S. Sizer, et al. appear to be the most pertinent.
None of the prior art with which applicant is familiar discloses an injector device having a chain drive mechanism with two longitudinally spaced apart gripping areas either one of which is capable of gripping and driving the pipe string and being selectively, individually and independently operated, permitting each of these gripping sections to open in turn so that a pipe coupling or other similar enlargement may pass through the device, one of the gripping sections always driving the pipe while the other gripping section is opened or released to permit passage of such coupling or enlargement, the forces applied to each of the gripping areas being transmitted to the drive chains through use of pressure beams which are moved toward and away from the pipe string by hydraulic means.
U.S. Pat. Nos. 3,285,485 to D. T. Slator, 3,559,905 to Alexander Palynchuk, and 4,515,220 to Phillip S. Sizer, et al. are hereby incorporated herein for all purposes by reference thereto.